Microbial community divergence and environmental responses across multi-phase landfill environments

Area of Science:

• Environmental microbiology
• Geomicrobiology
• Waste management science

Background:

• Municipal solid waste landfills are complex ecosystems with poorly understood microbial dynamics.
• Limited data exists on landfill microbiome structure across depth profiles and environmental gradients.

Purpose of the Study:

• To characterize landfill microbiomes in detail across multi-phase and depth profiles.
• To propose a solid-phase stabilization index (β) for quantifying waste degradation stages.
• To investigate microbial responses to environmental gradients and leachate-soil interactions.

Main Methods:

• Deep drilling up to 50 meters for sample collection.
• 16S rRNA gene sequencing for microbiome profiling.
• Biogeochemical pathway analysis and development of a solid-phase stabilization index (β).

Main Results:

• A clear microbial succession was observed, transitioning from Firmicutes-dominated rapid degradation (β < 0.58) to Proteobacteria-dominated stabilization (β > 0.83).
• Distinct microbial niche partitioning was identified between solid waste (biofilm formers like Advenella, Brevundimonas) and leachate (thermophilic Defluviitoga).
• Leachate infiltration at the waste-soil interface enriched dual-tolerant Ralstonia, and heavy metals (Cu, Be, Cd) significantly influenced subsoil microorganisms.

Conclusions:

• The study provides a multidimensional characterization of landfill microbiomes, advancing understanding of waste stabilization.
• The proposed stabilization index (β) effectively links microbial succession to degradation stages.
• Findings offer insights into landfill maturity assessment, leachate-soil interactions, and pollution front evolution.